Dynamic Soundscape Research Articles

EchoSee: An Assistive Mobile Application for Real-Time 3D Environment Reconstruction and Sonification Supporting Enhanced Navigation for People with Vision Impairments.

Improving the quality of life for people with vision impairments has been an important goal in the research and design of assistive devices for several decades. This paper seeks to further that goal by introducing a novel assistive technology platform that leverages real-time 3D spatial audio to promote safe and efficient navigation for people who are blind or visually impaired (PVI). The presented platform, EchoSee, uses modern 3D scanning technology on a mobile device to construct a live, digital 3D map of a user's environment as they move about their surroundings. Spatialized, virtual audio sources (i.e., virtual speakers) are dynamically placed within the digital 3D scan of the world, providing the navigator with a real-time 3D stereo audio "soundscape." The digital 3D map, and its resultant soundscape, are continuously updated as the user moves about their environment. The generated soundscape is played back through headphones connected to the navigator's device. This paper details (1) the underlying technical components and how they were integrated to produce the mobile application that generates a dynamic soundscape on a consumer mobile device, (2) a methodology for analyzing navigation performance with the application, (3) the design and execution of a user study investigating the effectiveness of the presented system, and (4) a discussion of the results of that study along with a proposed future study and possible improvements. Altogether, this paper presents a novel software platform aimed at assisting individuals with vision impairments to navigate and understand spaces safely, efficiently, and independently and the results of a feasibility study analyzing the viability of the approach.

Natural soundscape variation appears to influence the structure of stereotypic calls and repertoires in killer whales

Underwater soundscapes show dynamic variations in natural ambient sound levels at different locations and water depths and levels can vary over a course of a day. This soundscape dynamicity may pose a vocal challenge for highly mobile marine mammals whose habitat overlaps with many dynamic soundscapes. The most prominent communication tool of killer whales is a pulsated often multicomponent call which can be detected at more than 15 kilometers under quiet conditions. Social learning of call structure is a driver for stereotypic long lasting group- or population-specific call repertoires. Here we describe the potential vocal adaptations of killer whales to reduce the influence of sound propagation loss (PL) on their calls. Reliable propagation to identify groups and populations at considerable distances is important. In experimental field trials, the PL of killer whale calls and that of tones and sweeps was examined to determine if call component PL differs among soundscapes. PL is positively correlated with spatial and temporal ambient noise level variation. Furthermore, the use of burst pulses, a common feature of calls increased propagation distances at higher noise levels. We conclude that noise variation is one of the drivers of call structure and may also influence the call repertoire size.

Adaptive echolocation behavior of bats and toothed whales in dynamic soundscapes.

Journal of Experimental Biology has a long history of reporting research discoveries on animal echolocation, the subject of this Centenary Review. Echolocating animals emit intense sound pulses and process echoes to localize objects in dynamic soundscapes. More than 1100 species of bats and 70 species of toothed whales rely on echolocation to operate in aerial and aquatic environments, respectively. The need to mitigate acoustic clutter and ambient noise is common to both aerial and aquatic echolocating animals, resulting in convergence of many echolocation features, such as directional sound emission and hearing, and decreased pulse intervals and sound intensity during target approach. The physics of sound transmission in air and underwater constrains the production, detection and localization of sonar signals, resulting in differences in response times to initiate prey interception by aerial and aquatic echolocating animals. Anti-predator behavioral responses of prey pursued by echolocating animals affect behavioral foraging strategies in air and underwater. For example, many insect prey can detect and react to bat echolocation sounds, whereas most fish and squid are unresponsive to toothed whale signals, but can instead sense water movements generated by an approaching predator. These differences have implications for how bats and toothed whales hunt using echolocation. Here, we consider the behaviors used by echolocating mammals to (1) track and intercept moving prey equipped with predator detectors, (2) interrogate dynamic sonar scenes and (3) exploit visual and passive acoustic stimuli. Similarities and differences in animal sonar behaviors underwater and in air point to open research questions that are ripe for exploration.

Effects of environmental music therapy on anxiety and waiting in radiation oncology

A randomized control trial investigated perceived waiting time in patient and caregivers, and live music’s effects on anxiety levels prior to daily radiation therapy (RT). Environmental Music Therapy (EMT) is a live music intervention by music therapists meant to modify perception of potentially stressful environments through constructing dynamic soundscapes to provide enhanced comfort and safety. This study (a) rated participants’ state anxiety and distress experienced in the waiting area pre-RT, (b) determined if the EMT protocol moderated baseline treatment experience-related anxiety and (c) evaluated EMT’s affects on perceived waiting time pre-treatment, versus actual waiting time. We hypothesized EMT would reduce state anxiety, distress, and regulate distortion of waiting time, ultimately changing overall RT perception. 160 randomized patients and caregivers were accrued- 82 receiving EMT, 78 randomized to control. Assessment pre/post intervention measured anxiety and distress with the STAI 6 and Visual Analogue Distress Scale. A time survey assessed waiting perception. Data collected and recorded by research assistants naïve to treatment conditions found EMT interventions showed significantly reduced perceived incidences of anxiety and distress, significantly shortening perceived waiting times in the EMT arm compared to controls. Reduced anxiety, distress, and temporal distortion can enhance patients’ and caregivers’ perception of hospital environments.

Assistive mobile application for real-time 3D spatial audio soundscapes toward improving safe and independent navigation

Assistive technologies are used in a variety of contexts to improve the quality of life for individuals that may have one or more vision impairments. This paper describes a novel assistive technology platform that utilizes real-time 3D spatial audio to aid its users in safe and efficient navigation. This platform leverages modern 3D scanning technology on a mobile device to digitally construct a live 3D map of a user's surroundings as they move about their space. Within the digital 3D scan of the world, spatialized, virtual audio sources (i.e., speakers) provide the navigator with a real-time 3D stereo audio "soundscape." As the user moves about the world, the digital 3D map, and its resultant soundscape, are continuously updated and played back through headphones connected to the navigator's device. This paper details (1) the underlying technical components and how they were integrated to produce the mobile application that generates a dynamic soundscape on a consumer mobile device and (2) a methodology for analyzing the usage of the application. It is the aim of this application to assist individuals with vision impairments to navigate and understand spaces safely, efficiently, and independently.

Pitch, Timbre and Intensity Interdependently Modulate Neural Responses to Salient Sounds

As we listen to everyday sounds, auditory perception is heavily shaped by interactions between acoustic attributes such as pitch, timbre and intensity; though it is not clear how such interactions affect judgments of acoustic salience in dynamic soundscapes. Salience perception is believed to rely on an internal brain model that tracks the evolution of acoustic characteristics of a scene and flags events that do not fit this model as salient. The current study explores how the interdependency between attributes of dynamic scenes affects the neural representation of this internal model and shapes encoding of salient events. Specifically, the study examines how deviations along combinations of acoustic attributes interact to modulate brain responses, and subsequently guide perception of certain sound events as salient given their context. Human volunteers have their attention focused on a visual task and ignore acoustic melodies playing in the background while their brain activity using electroencephalography is recorded. Ambient sounds consist of musical melodies with probabilistically-varying acoustic attributes. Salient notes embedded in these scenes deviate from the melody’s statistical distribution along pitch, timbre and/or intensity. Recordings of brain responses to salient notes reveal that neural power in response to the melodic rhythm as well as cross-trial phase alignment in the theta band are modulated by degree of salience of the notes, estimated across all acoustic attributes given their probabilistic context. These neural nonlinear effects across attributes strongly parallel behavioral nonlinear interactions observed in perceptual judgments of auditory salience using similar dynamic melodies; suggesting a neural underpinning of nonlinear interactions that underlie salience perception.

Victorian gothic soundscapes

AbstractResounding with wails, groans, creaks, thunders, bells, and a score of other unsettling and often unidentifiable sounds, the Victorian gothic emerges against the backdrop of what John M. Picker has called “a period of unprecedented amplification” that necessitated new modes of listening. While critics have increasingly acknowledged the significance of the audible world to Victorian literature, and sound studies has exposed new approaches to addressing the acoustic dimensions of texts, the gothic soundscape remains largely unexamined. This article identifies the shared qualities of the sonic world and Victorian gothic fiction, building on two key definitions of sound to expose how the genre absorbed, manipulated, and leveraged the soundscape to spark terror among characters and readers alike. It then offers an overview of scholarship on the gothic and sound, focusing primarily on the past twenty years. Although a number of critics investigate the role of music in gothic fiction by Ann Radcliffe, Charles Dickens, George Eliot, and Wilkie Collins, among others, few move beyond it to consider the soundscape in its entirety. The final section calls attention to some of the shared keynotes among Victorian gothic texts and suggests possible approaches to more sustained scholarly work on their dynamic soundscapes.

An open architecture for auralization of dynamic soundscapes

An open architecture for auralization has been developed by NASA to support research aimed at understanding human response to sound within a complex and dynamic soundscape. The NASA Auralization Framework (NAF) supersedes an earlier auralization tool set developed for aircraft flyover noise auralization and serves as a basis for a future auralization plug-in for the NASA Aircraft Noise Prediction Program (ANOPP2). It is structured as a set of building blocks in the form of dynamic link libraries, so that other soundscapes, e.g., those involving ground transportation, wind turbines, etc., and other use cases, e.g., inverse problems, may easily be accommodated The NAF allows users to access auralization capabilities in several ways. The NAF's built-in functionality may be exercised utilizing either basic (e.g., console executable) or advanced (e.g., MATLAB, LabView, etc.) host environments. The NAF’s capabilities can also be extended by augmenting or replacing major activities through programming its open architecture. In this regard, it is envisioned that third parties will develop plug-in capabilities to augment those included in the NAF.

Change detection in complex acoustic scenes

The notion that sensitivity to temporal regularity (TR) plays a pivotal role in auditory scene analysis (ASA) has recently garnered considerable attention. Nevertheless, evidence supporting a primary role for TR is based on experiments employing simple stimuli consisting of one, or two, concurrent sound sequences. Whether the role of TR in mediating ASA is robust to more complex listening environments is unknown. The present study investigates sensitivity to TR in the context of a change detection task, employing complex acoustic scenes comprised of up to 14 concurrent auditory objects. Sequences of sounds produced by each object were either temporally regular (REG) or irregular (RAND). Listeners had to detect occasional changes (appearances or disappearances of an object) within these “soundscapes.” Listeners' performance depended on the TR of both the changing object and the scene context (TR of other objects in the scene) such that RAND contexts were associated with slower response times and substantially reduced detection performance. Therefore, even in complex scenes, sensitivity to TR is critical to our ability to analyze and detect changes in a dynamic soundscape. Importantly, the data reveal that listeners are able to acquire the temporal patterning associated with at least 14 concurrently presented objects.

What is soundscape ecology? An introduction and overview of an emerging new science

We summarize the foundational elements of a new area of research we call soundscape ecology. The study of sound in landscapes is based on an understanding of how sound, from various sources—biological, geophysical and anthropogenic—can be used to understand coupled natural-human dynamics across different spatial and temporal scales. Useful terms, such as soundscapes, biophony, geophony and anthrophony, are introduced and defined. The intellectual foundations of soundscape ecology are described—those of spatial ecology, bioacoustics, urban environmental acoustics and acoustic ecology. We argue that soundscape ecology differs from the humanities driven focus of acoustic ecology although soundscape ecology will likely need its rich vocabulary and conservation ethic. An integrative framework is presented that describes how climate, land transformations, biodiversity patterns, timing of life history events and human activities create the dynamic soundscape. We also summarize what is currently known about factors that control temporal soundscape dynamics and variability across spatial gradients. Several different phonic interactions (e.g., how anthrophony affects biophony) are also described. Soundscape ecology tools that will be needed are also discussed along with the several ways in which soundscapes need to be managed. This summary article helps frame the other more application-oriented papers that appear in this special issue.